Multi-electrode impedance sensing

Abstract

A system and method for assessing contact between a medical device and tissue may comprise an electronic control unit (ECU) configured to be coupled to a medical device, the medical device comprising a first electrode and a second electrode. The ECU may be further configured to select the first electrode as an electrical source and the second electrode as an electrical sink, to cause an electrical signal to be driven between the source and sink, to detect respective electric potentials on the first electrode and the second electrode while the electrical signal is driven, and to determine an impedance respective of one of the first electrode and the second electrode according to both of the respective electric potentials.

1 - 20 . (canceled) 
     
     
         21 . A system for assessing a contact state between a medical device and a tissue, wherein the medical device comprises a catheter having a distal portion and a plurality of electrodes within the distal portion, the system comprising:
 a signal generator operably coupled to the plurality of electrodes;   a detection amplifier operably coupled to the plurality of electrodes; and   an electronic control unit (ECU) operably coupled to the signal generator and the detection amplifier, wherein the ECU is configured to:
 cause the signal generator to generate an excitation signal for delivery to the plurality of electrodes; 
 cause the detection amplifier to measure electrical potentials at the plurality of electrodes; 
 determine the contact state between the catheter and the tissue from the measured electrical potentials; and 
 output an indication of the contact state between the catheter and the tissue. 
   
     
     
         22 . The system according to  claim 21 , wherein the ECU is further configured to cause the detection amplifier to measure electrophysiology data from the tissue using the plurality of electrodes. 
     
     
         23 . The system according to  claim 22 , wherein the ECU is further configured to cause the detection amplifier to measure the electrophysiology data from the tissue using the plurality of electrodes when the contact state between the catheter and the tissue is that the catheter is in contact with the tissue. 
     
     
         24 . The system according to  claim 21 , wherein the excitation signal drives a current between a pair of electrodes of the plurality of electrodes. 
     
     
         25 . The system according to  claim 21 , wherein the ECU is further configured to determine impedances at the plurality of electrodes from the measured electrical potentials at the plurality of electrodes and to determine the contact state between the catheter and the tissue from the impedances at the plurality of electrodes. 
     
     
         26 . The system according to  claim 21 , wherein the contact state comprises a binary contact state. 
     
     
         27 . The system according to  claim 21 , wherein the measured electrical potentials are measured with reference to an additional electrode that is not amongst the plurality of electrodes within the distal portion of the catheter. 
     
     
         28 . The system according to  claim 27 , wherein the additional electrode comprises a patch electrode applied to a body surface of a patient. 
     
     
         29 . A system comprising:
 a catheter having a distal portion and including a plurality of electrodes disposed within the distal portion;   an electronic control unit (ECU) coupled to the catheter, wherein the ECU is configured to:
 drive one or more electrodes of the plurality of electrodes with an electrical signal; 
 detect respective electrical potentials on the plurality of electrodes while the one or more electrodes of the plurality of electrodes are driven with the electrical signal; 
 determine a contact state between the catheter and a tissue; and 
 output an indication of the contact state between the catheter and the tissue. 
   
     
     
         30 . The system according to  claim 29 , wherein the ECU is configured to drive the electrical signal from a first electrode of the plurality of electrodes to a second electrode of the plurality of electrodes. 
     
     
         31 . The system according to  claim 29 , wherein the contact state comprises a binary contact state. 
     
     
         32 . The system according to  claim 29 , wherein the electrical potentials are referenced to an electrical potential at an additional electrode that is not amongst the plurality of electrodes within the distal portion of the catheter. 
     
     
         33 . The system according to  claim 32 , wherein the additional electrode comprises a patch electrode applied to a body surface of a patient. 
     
     
         33 . The system according to  claim 29 , wherein the ECU is further configured to measure electrophysiology data from the tissue using the plurality of electrodes. 
     
     
         34 . The system according to  claim 33 , wherein the electrophysiology data is measured when the catheter is in contact with the tissue. 
     
     
         35 . A method of assessing a contact state between a medical device and a tissue, wherein the medical device comprises a catheter having a distal portion and a plurality of electrodes within the distal portion, the method comprising:
 causing an electronic control unit (ECU) to command a signal generator to generate an excitation signal for delivery to the plurality of electrodes;   causing the ECU to command a detection amplifier to measure electrical potentials at the plurality of electrodes;   determining, in the ECU, the contact state between the catheter and the tissue from the measured electrical potentials; and   outputting, from the ECU, an indication of the contact state between the catheter and the tissue.   
     
     
         36 . The method according to  claim 35 , wherein the indication of the contact state comprises one of an indication that the catheter is in contact with the tissue and an indication that the catheter is not in contact with the tissue. 
     
     
         37 . The method according to  claim 35 , further comprising causing the ECU to command the detection amplifier to measure electrophysiology data from the tissue using the plurality of electrodes. 
     
     
         38 . The method according to  claim 37 , wherein the ECU commands the detection amplifier to measure the electrophysiology data from the tissue when the ECU determines that the catheter is in contact with the tissue. 
     
     
         39 . The method according to  claim 35 , further comprising determining, in the ECU, impedances at the plurality of electrodes from the measured electrical potentials at the plurality of electrodes, and wherein determining, in the ECU, the contact state between the catheter and the tissue comprises determining, in the ECU, the contact state between the catheter and the tissue from the impedances at the plurality of electrodes. 
     
     
         40 . The method according to  claim 39 , wherein the plurality of impedances comprises a plurality of bipolar impedances measured between pairs of electrodes of the plurality of electrodes.